Justification:Scarus guacamaia is the largest parrotfish in the Atlantic, reaching a maximum size in excess of 100 cm. It is relatively widespread in the western Atlantic from Bermuda through south Florida, the Bahamas and the Caribbean to Venezuela. It is naturally rare, a characteristic that is shared by other large-bodied labrids. It achieves high densities only in areas that are protected from exploitation and habitat degradation, with highest densities recorded in areas that have long been protected from exploitation (e.g., Bermuda, Bonaire and Los Roques). There have been significant decreases in species densities recorded over a gradient of fishing pressure, human densities and presence or absence of species protection through marine reserves. Densities of large-bodied parrotfish are 10-fold lower in areas where fishing is present than in areas where fishing is restricted (Debrot et al. 2008). Scarus guacamaia has experienced significant historical declines. In most of its range, this species is still fished, but given its current and natural rarity it is not often caught. This species is also threatened by the continued loss of coral reef and mangrove habitat from coastal development and extraction. Based on anecdotal information from Glovers Reef in the Caribbean (D. Wesby pers comm 2009), S. guacamaia has undergone local extinction in the past 30 years. Schools of this parrotfish were commonly observed in the 1960s when several of the islands had well-developed mangrove habitats (Mumby et al. 2004). This species appears to be uncommon elsewhere in its range.

Scarus guacamaia is usually associated with shallow waters and in reefs with extensive sheltered lagoonal/backreef areas. There are a number of parallels with Bolbometopon muricatum, the largest parrotfish in the in the Indo-Pacific, currently listed as Vulnerable on the IUCN Red List of Threatened Species. Intrinsic life history characteristics such as large size, natural rarity and shallow foraging areas render them particularly susceptible to overfishing (particularly spearfishing). Both species recruit into very shallow water, sheltered reef and mangrove sites that are increasingly impacted by habitat modification and degradation. S. guacamaia is experiencing > 30% decline and destruction of coral reef habitat which makes up 7% of its range and is exposed to extensive mangrove deforestation in many parts of its distributional range. Unlike B. muricatum, which inhabits a wide oceanic basin and could find refuge on isolated oceanic islands in the Indo-Pacific, S. guacamaia inhabits a smaller oceanic habitat and may not have access to the types of refuge available for B. muricatum.

In summary, there are several biological features of major significance to population reductions of this species due to extrinsic threats: 1) natural rarity of S. guacamaia; 2) large size; 3) shallow depth range (to 30 m) and propensity to occupy, recruit and forage in shallow sites. In addition to the impacts of exploitation, this species utilizes habitats that are increasingly impacted and have experienced significant loss in the last 20–30 years. Although significant declines have been reported, the lack of adequate historical population data combined with the rarity of current sightings and subsequent difficulty in coordinating efforts to determine its current population size has resulted in the inability to effectively quantify population declines over time. Moreover, S. guacamaia appears to be conservation dependent with recorded densities highest only in areas where protection is present. It is therefore listed as Near Threatened at the very minimum because cessation of conservation measures could result in this species qualifying for one of the threatened categories within a period of five years. We recommend further monitoring of this species’ population and habitat status and a comprehensive analysis of the reproductive biology including gonadal studies to confirm estimates of size and age at first maturity, estimates of age and sex-specific growth rates, and mortality estimates. In addition, a more detailed analysis of demographic and abundance data is needed in order to predict population responses to varying rates of fishing pressure.

Scarus guacamaia is relatively widely distributed in the western Atlantic from Bermuda through south Florida, the Bahamas and the Caribbean to Venezuela.

There are dubious records from Brazil (Floeter et al. 2005) which are based on few specimens from museums and literature records. Although Ferreira et al. (2005) suggest that S. guacamaia is locally extinct, this species is confirmed as a vagrant along the Brazilian coast.

Scarus guacamaia has experienced significant historical declines. In most of its range, this species is still fished, but given its current and natural rarity it is not often caught. This species is also threatened throughout its range from the continued loss of coral reef and mangrove habitat from coastal development and extraction. Based on anecdotal information from Glovers Reef in the Caribbean (D. Wesby pers comm 2009), S. guacamaia has undergone local extinction in the past 30 years. Schools of this parrotfish were commonly observed in the 1960s when several of the islands had well-developed mangrove habitats (Mumby et al. 2004). Within this species' range, aggregated parrotfish catch landings show an increase that began in 2000 with a spike in 2003 and a 27% decline since then (FAO 2012). The pattern in catch landings are concordant to the shift in target preference to herbivorous fishes and planktivores with the removal of the piscivores (Butler et al. 1993, Debrot et al. 2008, Mumby et al. 2012).

Scarus guacamaia is naturally rare, a characteristic that is shared by other large labrids (Choat et al. 2006). However, it achieves relatively high densities in protected areas; for example, ~16 individuals/10,000 m² were observed in Bonaire, where it has been protected since 1979 (J.H. Choat pers comm. 2012) and 9.30 ± 3.79 ind/1,000 m² were recorded in Los Roques, where fishing is restricted (Debrot et al. 2008). In comparison, densities of S. guacamaia and other big-bodied parrotfishes at four localities in the Caribbean open to fishing were 10-fold lower than those within the Los Roques marine reserve, and were absent in Barbados where there was an extensive trap fishery for reef fishes and where parrotfishes are prized components of the reef fishery (Debrot et al. 2008). In Las Aves archipelago, an uninhabited area with an uncontrolled fishery targeting piscivorous reef fishes, only 0.4 individuals/10,000 m² were recorded for this species, while 15–16 individuals/10,000 m² were recorded for Scarus coelestinus, a large-bodied scarine (J.H. Choat pers comm. 2012). In Bermuda, where parrotfishes have been protected since 1978, this species was observed in big schools (15–30 individuals) (J.H. Choat pers. comm. 2012). Providing further support of the conservation dependency of this species, in a marine reserve in the Bahamas, the Exuma Cays Land and Sea Park, protection has resulted in an increase in total biomass inside the reserves for large-bodied parrotfishes such as Scarus vetula, although S. guacamaia was not reported in this study (Mumby 2006). This species appears to be uncommon elsewhere in its range (San Blas, Lee Stocking Island, Bahamas, Barbados, Belize, Curacao, St. Croix, St. Thomas, Jamaica and Margarita Island). and at a number of locations only small individuals were seen but none were recorded in counts (J.H. Choat pers comm. 2012).

Scarus guacamaia is the largest parrotfish in the Atlantic (Dorenbosch et al. 2006, Bellwood and Choat 2011) reaching a maximum size of 1.2 m (Choat et al. 2006) and a maximum age of 16 years (J.H. Choat pers comm. 2012). This species recruits primarily to mangroves (Mumby et al. 2004, Dorenbosch et al. 2006, Mumby and Hastings 2008, Bellwood and Choat 2011), and although it is suggested to be functionally dependent on mangroves, juveniles have been collected on rocks in Bermuda and adults have been found on isolated rocky islands 30–50 km from the nearest mangroves off the coast of Venezuela (Robertson pers comm. 2012). This species therefore appears to recruit to a variety of habitats. Scarus guacamaia is classified as a detritivore, with detritus/bacterial complexes and meiofauna as the primary food items. It also feeds on sponges (Dunlap and Pawlik 1998) and feeds more similarly to Sparisoma spp. particularly Sparisoma viride, than to other Scarus spp. (Burkepile and Hay 2011).

Scarus guacamaia is usually associated with shallow waters and in reefs with extensive sheltered lagoonal/backreef areas (J.H. Choat pers comm. 2012). There are a number of parallels with Bolbometopon muricatum, the largest parrotfish in the Indo-Pacific, currently listed as Vulnerable on the IUCN Red List of Threatened Species. Intrinsic life history characteristics such as large size, natural rarity and shallow foraging areas render both species particularly susceptible to overfishing (particularly spearfishing). In addition, both species recruit into very shallow water, sheltered reef and mangrove sites that are increasingly impacted by habitat modification and degradation. Unlike B. muricatum, which inhabits a wide oceanic basin and could find refuge on isolated oceanic islands in the Indo-Pacific, S. guacamaia inhabits a smaller oceanic habitat and may not have access to the types of refuge available for B. muricatum.

More than 30% (37%) of coral reef habitat within the distributional range of S. guacamaia has been destroyed or is declining; this coral reef habitat makes up 7% of the species' range (Comeros-Raynal in prep.). In addition, the Caribbean region has the second highest mangrove area loss relative to other global regions with ~24% of mangrove area lost over the past 25 years (FAO 2007, Polidoro et al. 2010). The greatest rate of mangrove deforestation is occurring in the Americas (2,251 km²/year) and exceeds that of tropical rainforests (Mumby et al. 2004).

Parrotfishes show varying degrees of habitat preference and utilization of coral reef habitats, with some species spending the majority of their life stages on coral reefs, while others primarily utilize seagrass beds, mangroves, algal beds, and /or rocky reefs. Although the majority of the parrotfishes occur in mixed habitat (primarily inhabiting seagrass beds, mangroves, and rocky reefs) approximately 78% of these mixed habitat species are experiencing greater than 30% loss of coral reef area and habitat quality across their distributions. Of those species that occur exclusively in coral reef habitat, more than 80% are experiencing a greater than 30% of coral reef loss and degradation across their distributions. However, more research is needed to understand the long-term effects of habitat loss and degradation on these species populations. Widespread coral reef loss and declining habitat conditions are particularly worrying for species that depend on live coral reefs for food and shelter especially as studies have shown that protection of pristine habitats facilitate the persistence of adult populations in species that have spatially separated adult and juvenile habitats. Furthermore, coral reef loss and declining habitat conditions are particularly worrying for some corallivorous excavating parrotfishes that play major roles in reef dynamics and sedimentation (Comeros-Raynal et al. 2012).

This species is found in a number of marine reserves in parts of its range. Furthermore, in Bermuda all species of parrotfishes are protected under the Fisheries (Protected Species) Order 1978. In addition, there have been recent protective measures put in place for parrotfishes in Belize, wherein the fishing of grazers, defined as any scarinae species and Acanthuridae species, is prohibited. In the Turks and Caicos, the fishing and selling of any species of parrotfish is prohibited, and the Caribbean Management Council, which comprises the Commonwealth of Puerto Rico and United States Virgin Islands, has prohibited the harvest and possession of Midnight Parrotfish (Scarus coelestinus), Blue Parrotfish (Scarus coeruleus), and S. guacamaia and reduced parrotfish harvest in St. Croix. In Bonaire, a recent law (instated in 2010) was passed banning the harvesting of parrotfish (Steneck et al. 2011).

Debrot, D., Choat, J.H., Posada, J.M. and Robertson, D.R. 2008. High Densities of the Large Bodied Parrotfishes (Scaridae) at Two Venezuelan Offshore Reefs: Comparison Among Four Localities in the Caribbean. Proceedings of the 60th Gulf and Caribbean Fisheries Institute : 335-338.